Cable lock shoe

ABSTRACT

A cable lock shoe is provided that has a side portion that includes sections that are arranged at a slight angle with respect to each other. Thus, the angle of the cable side of the shoe is parallel to the sloping side of the shoe from a point centered with the cam center line and this permits the shoe to clamp the cable when it moves upward without increasing pressure on the cam.

United States Patent [191 McElroy 11] 3,907,255 Sept. 23, 1975 CABLE LOCK SHOE [75] Inventor: Robert McElroy, Lisbon, Ohio [73] Assignee: Cable Climber Safety Devices,

Incorporated, Lisbon, Ohio [22] Filed: Apr. 4, 1974 21 Appl, No.: 458,001

[52] US. Cl 254/156; 188/188; 24/136 B [51] Int. Cl. A62B 1/14 [58] Field of Search 254/156,- 191; 104/239; 188/188,189, 65.1; 24/136 B, 263 SC, 250 R; 294/74 R [56] References Cited UNITED STATES PATENTS 1,164,980 12/1915 Bergenroth 254/156 2,493,556 1/1950 Stone 24/136 B 2,508,187 5/1950 Niemiec 254/156 2,922,623 1/1960 Simmons... 254/156 3,333,822 8/1967 Horvath..... 254/156 3,669,223 6/1972 Arnold 188/188 Primary Examiner-Robert J. Spar Assistant Exa'minerl(enneth Noland Attorney, Agent, or Firm-Blair & Brown [57] ABSTRACT A cable lock shoe is provided that has a side portion that includes sections that are arranged at a slight angle with respect to each other. Thus, the angle of the cable side of the shoe is parallel to the sloping side of the shoe from a point centered with the cam center line and this permits the shoe to clamp the cable when it moves upward without increasing pressure on the cam.

2 Claims, 5 Drawing Figures CABLELOCK SHOE BACKGROUND OF THE INVENTION FIELD OF THE INVENTION The present invention relates to electric hoists, and more particularly to improved cable lock shoes for such hoists.

SUMMARY OF THE INVENTION A cable lock shoe is provided for an electric hoist wherein the action or. movement of the parts is made more efficient as compared to previous constructions. In accordance with the present invention the angle of the cable side of the shoe has been changed so that it is parallel to the sloping side of the shoe from a point centered with the cam center line. This construction permits the shoe to clamp the cable when it moves upward. withoutincreasing pressure on the cam. 1

The primary object of the present invention is to provide a cable lock shoe that will insure that the action and movement of the parts will perform with increased efficiency and wherein the shoe. can clamp the cable when it moves upward without increasing pressure on the cam. v v

Yet another object of the present invention is to provide a cable lock shoe that is relatively economical to manufacture and efficient in operation and which is rugged in structure and efficient in use. 7

Still other objects and advantages will become apparent in the following specification when considered in light of the attached drawings.

BRIEF DESCRIPTION OF THE DRAWINGS FIG. 1 is a fragmentary elevational view illustrating the present invention;

FIG. 2 is a vertical sectional view;

FIG. 3 is a view generally taken on the line 3-3 of FIG. 2;

FIG. 4 is an end view thereof; and

FIG. 5 is a perspective view of the cable lock shoe of the present invention.

DESCRIPTION OF THE PREFERRED EMBODIMENT Referring now to the drawings in detail, wherein like reference characters indicate like parts throughout the several figures, the reference numeral 70 indicates the improved cable lock shoe of the present invention that is used as an attachment for an electric hoist and an improvement over prior electric hoists such as that shown in prior US. Pat. No. 3,333,822, issued Aug. 1, 1967.

As shown in the drawings of the present invention a pair of plates l7, 18 are secured together in spaced parallel relation by means of securing elements such as bolts and nuts. A block 29 is connected to the upper end of plate 18 by a suitable bolt and nut assembly 19 and a bolt 30. The block 29 has an annular recess 31 that is closed by the plate 18. A stub shaft 32 extends through the block 29, the block recess 31 and plate 18 being rotatably supported thereby and having an offset cam 33 integral with the stub shaft 32. The periphery of the cam 33 is provided with an annular groove 34 which is adapted to receive a portion of cable A therein as shown in the drawings.

A roller 35 has a stop 35a extending from its inner face and an annular recess 36 in its outer face in which is positioned a coil spring 37. An L shaped handle 40 is connected to the roller 35 by bolts 41. The roller 35 is provided with a peripheral recess 42 defined by a reduced diameter portion of the roller 35. An end portion 43 of the stub shaft 32 and the roller 35 are keyed together by a key 44 that is retained in place by means of a washer 45 and bolt 46 which are arranged in threaded engagement with the stub shaft 32.

As shown in thedrawings there is provided a pawl 47 which is pivotally' mounted on the end of the stub shaft 32, and a screw 48 extends from the pawl 47. A cam 49 is fixedly attached to the stub shaft 32 by a plurality of set screws 49a and has a peripheral recess 49b with screw members 48 positioned within the recess 49b as shown in the drawings.

The pawl 47 has an inverted L shaped configuration and has teeth 51 in an end of one leg thereofQThe pawl 47 hasa second leg 52 that is provided with an end recess 53. A stub shaft 54 is secured to or integral with the shoe 71, and the stub shaft 54 extends laterally of the shoe 71, and into recess 53. The-block 29 has an elongated recess 55 of which one side is tapered at 72, and the shoe 71 is slidable in the recess 55 with a tapered side 73 abutting the tapered side 72 of the recess 55. A coil spring 57 is seated within the top recess 56a of the shoe 71, and the coil spring is held in place by a retainer plate 74 maintained in its proper location by means of securing elements 75, 76 and 77, FIG. 3. The spring 57 urges the shoe 71 towards the bottom of the recess 55. A normally open micro-switch 61 is supported beneath the roller 35 and has an operating plunger 62 for normally engaging the periphery of roller 35 within recess 42 for leaving the micro-switch 61 open until the handle 40 is pivoted to the left in FIG. 1, when the plunger 62 is depressed by the roller 35 closing the micro-switch 61.

The block 29 has a groove 63 that extends the height thereof and the groove 63 communicates with recesses 31 and 55 and is of a diameter for slidably receiving therein the cable A so that the cable can pass downwardly and around the drum (not shown). The shoe 71 has a longitudinally extending groove 78 therein, and the groove 78 has a cable A normally slidably mounted for riding therein as shown in the drawings.

The cable side 79 of the shoe 71 is shown in FIG. 5 while the numeral 73 indicates the sloping side thereof. The cable side 79 includes a lower portion 80 that is parallel with the sloping side of the shoe, and an upper portion 81 arranged at an angle with respect to the lower portion 80 as shown in the drawings.

From the foregoing, it will be seen that there has been provided an electric hoist which is an improvement over previous hoist such as that shown in prior US. Pat. No. 3,333,822. In accordance with the present invention there is provided the improved cable lock shoe 71. The cable lock shoe shown in prior US. Pat. No. 3,333,822 had one side straight, that is the cable side was straight. The cam pressed the cable against the side of the cable lock shoe which in turn caused an upward pressure on the shoe when the cable moved upward. The shoe compressed the cable A against the cable lock block to stop cable movement.

In accordance with the present invention certain disadvantages have been overcome, and it has been found that movement of the cable lock shoe was limited because the lower section of the shoe below the center line of the cam was wider restricting the movement upward of the shoe. As shown in FIG. 5 of the present application for example, the angle of the cable side of the shoe as indicated by the numeral 80 is parallel to the sloping side 73 of the shoe from a point centered with the cam center line. This permits the shoe 71 to clamp the cable and it moves upward without increasing pressure on the cam.

In addition with the present invention the recess 45 extends all the way to the top of the block, and the spring 57 is held in place by the retainer 74.

The operation is otherwise generally the same as the described in prior US. Pat. No. 3,333,822. Thus, the cable A is passed through openings 63 and can hang downwardly from a drum (not shown). The upper end of the cable A can be attached by any support (not shown) so that the same hangs therefrom. A load such as scaffolding, basket, may be attached to straps by fastening ropes (not shown) from the load through suitable openings. It will be noted that a drive motor can be actuated to move the hoist up or down the cable A as desired or required. Then the lever 40 can be pushed to close the micro-switch 61 and the drive motor will then turn pinions, gear wheels and the like so that the cable A will move the load upwardly or downwardly along the cable depending upon the direction of drive of the motor that is selected or being utilized.

Having thus described the preferred embodiment of the invention it should be understood that numerous structural modifications and adaptations may be resorted to without departing from the spirit of the invention.

What is claimed is:

'1. In an electric hoist for vertical movement on a stationary cable, a block on said hoist and movable therewith, a vertical recess in said block and having said cable extending therethrough adjacent one side thereof, said one side of said recess extending parallel to said cable and having a cable receiving groove extending therealong, the side of said recess opposite said groove sloping inwardly upwardly toward said cable, a generally circular recess formed in said block adjacent to and communicating with said vertical recess on said one side of said vertical recess, a cam mounted for rotation in said circular recess and adapted to engage said cable upon rotation of said cam, a cable lock shoe mounted for vertical sliding movement in said vertical recess, a downwardly and outwardly sloping wall on said shoe arranged in confronting relation to said inwardly sloping side of said vertical recess to move said shoe laterally in a cable clamping direction as said shoe moves upwardly in said recess, a groove formed in the side of said shoe toward said cable for engaging said cable, said side of said shoe toward said cable extending vertically from its upper end to a point intermediate its upper and lower end and then extending parallel to said downwardly and outwardly sloping wall for the rest of its length whereby the shoe does not bind against said cam when moving upwardly in a cable clamping direction.

2. A device as claimed in claim 1 wherein a recess is formed in the upper end of said block, a coil spring is seated in said last named recess and means on said block retains the upper end of said spring. 

1. In an electric hoist for vertical movement on a stationary cable, a block on said hoist and movable therewith, a vertical recess in said block and having said cable extending therethrough adjacent one side thereof, said one side of said recess extending parallel to said cable and having a cable receiving groove extending therealong, the side of said recess opposite said groove sloping inwardly upwardly toward said cable, a generally circular recess formed in said block adjacent to and communicating with said vertical recess on said one side of said vertical recess, a cam mounted for rotation in said circular recess and adapted to engage said cable upon rotation of said cam, a cable lock shoe mounted for vertical sliding movement in said vertical recess, a downwardly and outwardly sloping wall on said shoe arranged in confronting relation to said inwardly sloping side of said vertical recess to move said shoe laterally in a cable clamping direction as said shoe moves upwardly in said recess, a groove formed in the side of said shoe toward said cable for engaging said cable, said side of said shoe toward said cable extending vertically from its upper end to a point intermediate its upper and lower end and then extending parallel to said downwardly and outwardly sloping wall for the rest of its length whereby the shoe does not bind against said cam when moving upwardly in a cable clamping direction.
 2. A device as claimed in claim 1 wherein a recess is formed in the upper end of said block, a coil spring is seated in said last named recess and means on said block retains the upper end of said spring. 